Method for producing flip-flop shoe

Abstract

A method is provided for integrally forming a flip-flop shoe including a sole, a vamp having a toe slot, and a rib interconnected between the sole and the vamp. A sole cavity is defined between middle and lower molds. A vamp cavity is defined between upper and middle molds. An insertion block on the upper mold is received in a slot of the middle mold and corresponds to the toe slot. A rib cavity is defined between an end of the slot and the insertion block and intercommunicates with the sole cavity and the vamp cavity. Molten plastic material is filled into the sole cavity, the vamp cavity, and the rib cavity to form an integral flip-flop shoe including the sole, the vamp, the rib, and the toe slot. The upper and lower molds are then opened, and the integral flip-flop shoe is removed from the middle mold.

The invention claimed is: 
     
       1. A method for integrally forming a flip-flop shoe including a sole, a vamp integrally connected to an edge of the sole, and a rib interconnected between the sole and the vamp, with the sole, the vamp, and the rib integrally formed of a same material as an inseperable member, with the vamp adapted to extend around an instep and toes of a foot of a wearer, with the rib adapted to extend between two of the toes of the foot of the wearer, with the vamp including upper and lower sides and a toe slot extending from the upper side through the lower side of the vamp and aligned with the rib, and with the toe slot extending forwards to a location adjacent to a front edge of the vamp, with the method comprising:
 (A) preparing a mold device including an upper mold, a middle mold, and a lower mold corresponding to a shape of the flip-flop shoe, with the middle mold including a slot extending forwards and corresponding to the rib and the toe slot, and with the upper mold including an insertion block extending downwards and corresponding to the toe slot; 
 (B) actuating the mold device to close the upper and lower molds, with the middle mold located between the upper and lower molds, with a sole cavity for forming the sole defined between the middle mold and the lower mold, with a vamp cavity for forming the vamp defined between the upper mold and the middle mold, with the insertion block of the upper mold received in the slot of the middle mold, with a rib cavity for forming the rib defined between an end of the slot of the middle mold and the insertion block, and with the rib cavity having two ends intercommunicated with the sole cavity and the vamp cavity, respectively; 
 (C) filling molten plastic material into the sole cavity, the vamp cavity, and the rib cavity of the mold device to form an integral flip-flop shoe including the sole, the vamp, the rib, and the toe slot; and 
 (D) actuating the mold device to open the upper and lower molds, and removing the integral flip-flop shoe from the middle mold. 
 
     
     
       2. The method for integrally forming a flip-flop shoe as claimed in  claim 1 , with each of the upper mold and the middle mold including a plurality of protrusions in the vamp cavity, with the plurality of protrusions of the upper mold abutting the plurality of protrusions of the middle mold, forming a plurality of through-holes in the vamp of the flip-flop shoe. 
     
     
       3. The method for integrally forming a flip-flop shoe as claimed in  claim 1 , wherein the insertion block of the upper mold extends to a location adjacent to a front edge of the vamp cavity. 
     
     
       4. The method for integrally forming a flip-flop shoe as claimed in  claim 1 , with the sole cavity, the vamp cavity, and the rib cavity of the mold device having shapes smaller than shapes of the sole, the vamp, and the rib of the flip-flop shoe, with step (C) including filling molten plastic foam material into the mold device to form a foaming flip-flop shoe, and with step (D) including removing the flip-flop shoe in a foaming, expanding state from the middle mold. 
     
     
       5. The method for integrally forming a flip-flop shoe as claimed in  claim 4 , further comprising a step (E) of placing the flip-flop shoe in the foaming, expanding state on a shoe last and proceeding with cooling and shaping, and then removing an integrally foamed flip-flop shoe from the shoe last.